Water leaking in

Well my car's been in the shop for a week. The fuel pump wasn't getting any power, so the main relay was replaced and still nothing. It turns out, water is getting into the car from the rear somewhere and that the wires leading to the fuel pump were corroded as a result.

I knew there was a leak somewhere but didn't have the time or patience to find out. My laziness resulted in not having a car for a week.

The rear carpet behind the passenger seat is usually wet. The rear seats themselves are always dry, but I'm guessing the leak is going down somewhere behind the seats and down to the carpet.

Is there a common place where leaks usually get in? If there is rust because of it, how would I go about repairing it?

Mine leaked until I removed the rear window and sealed the body joints underneath. Now, dry as ever. You may want to check for water in the trunk (in the battery, jack, and spare tire wells). An automotive glass place performed this for me in a day. Pretty common leak. I read about the repair on another web site. You might check for rust under the back seat. Hope this helps.

I definitely have a leak in the trunk as well. I knew about this since I bought the car and about the leak in the passenger compartment as well, but never really paid much attention to it as I should have.

1) tail light gaskets. On the pre-facelift cars these are made of a foam material and will have deteriorated long ago. Easy to replace and not too expensive.

2) trunk seal. Over time these get compressed and hard allowing water to leak into the trunk. A quick test is to clean the seal and apply some Vaseline to the top where it contacts the trunk lid and then close the trunk. Open the trunk and then look to see if there are any areas where the Vaseline did not transfer to the trunk lid. These are potential leak spots.

3) Body plugs on the floor board. Look at these from the bottom side and make sure they are tight and still sealed. (These are about 5 inches in diameter and located in the center of each footwell area front and rear) If they have been pushed in or somehow dislodged get some automotive seam sealer from a local paint/body supply house, clean the area really well and apply the seam sealer. Almost all of my E30's have had loose body plugs from someone running over something at one point or another.

If all of the above check out then it may be a rear or side window seal.

The antenna grommet is an easy, cheap fix other than the fact that that little sucker is really hard to get in all the way. I think mine is in far enough to stop the water, but I can't get the little ridge that is supposed to be below the trunk deck in position. Anybody have advice on this?

I had a similar issue trying to get the grommet that's attached to the hood release cable in the hole fully when I was replacing the cable. I just stuck it in enough to cover the hole and left it at that.

The antenna grommet is an easy, cheap fix other than the fact that that little sucker is really hard to get in all the way. I think mine is in far enough to stop the water, but I can't get the little ridge that is supposed to be below the trunk deck in position. Anybody have advice on this?

Put the antenna down, put some soap or something else slippery that won't eat up the rubber grommet, then put an appropriately sized socket over it and tap the socket gently with a hammer to seat the grommet.

You can also leave the grommet lying out in the sun for a few hours before doing the above to soften it up.

1. remove trunk liner to access antenna
2. remove antenna bracket with standard hand tools and slide antenna down into trunk
3. remove old grommet: now that antenna is out, grommet removes easily
4. install new grommet: no lubricant is necessary
5. slide antenna back in using a little soap like dawn on top rubber portion of antenna, or use universal lubricant.........spit.
6. secure antenna bracket

Total time: 15-30 minutes
Any other way might damage fender

The antenna actually locks the grommet in place, which is why it must be removed to do job correctly